Means for preventing condensation in optical tubes.



PATENTED OCT. 2, 1906.

L.-Y. SPEAR. MEANS FOR PREVENTING GONDENSATION IN OPTICAL TUBES.

APPLICATION FILED DEC. 29, 1904.

of a

manner with reflectors and,

LAWRENCE Y. SPEAR, OF GREENPORT, BOAT COMPANY, OF GR NEW YORK, ASSIGNOR TO ELECTRIC EENPORT, NEW YORK.

MEANS FOR PREVENTING CONDENSATIONJN OPTICAL TUBES;

Specification of Letters Patent.

Patented Oct. 2,1906.

Original application filed May 26,1904, Serial N 0. 209,978. Divided and this application filed December 29,1904- Serial No- 238,796.

To all whom it may concern.-

Be it known that I, LAWRENCE Y. SPEAR, a citizen of the United States, residing in Greenport, in the county of Suffolk and State of New York, haveinvented certain new and useful Improvements in Means for Preventing Condensation in Optical Tubes, of which the following is a specification.

In the accompanying drawing, which illustrates an embodiment of the invention, the e is a longitudinal axial section of a part submarine boat and an optical tube mounted in the conning-tower thereof, said tube being provided with means for preventing condensation constructed according to the present invention.

In the figure, B designates a part of a .sub-

marine boat, and T a partv of the conning-' tower, turret, or sighting-hood of the boat. At the side of the turret T is an upright socket or sheath 1 to receive an o tical tube 2. This tube is fitted or supplied in any desirable if desired, with lenses in order to receive an image at its upper end and deflect the-same from its lower interior end into a substantially horizontal plane, where it may eyepiece 3 from the interior of the conningtower or turret. The tube may be fitted removably in its socket and be mounted so as to be rotatable about its vertical and longitudinal axis, and it may have suitable means for preventing access of water to the outer end of the socket and to enable it to rotate axially Without undue friction. The means herein shown for effecting these ends are substantially the same as'those shown in my United States Patent No. 751,569.

In the present construction the reflector at the u per end of the optical tube is a prism 4, inc osed in a box or casing 5, carried on the upper end of the tube. This prism turns with the tube, so as to face in any direction desired. The lower reflector is a prism 6, and it does not rotate with the tube, although it may do so as far as the present invention is concerned. This prism 6 is set or fitted in a fixed casting or hollow support 7, which has on its upper face a short cylindrical tube that fits accurately into the lower end of the opcal tube. The eyepiece is secured to or screwed into this casting 7 and has a Watertight connection with the front plate of a chamber C, which incloses the lower prism 6 valve '0 and in the be observed through an.

and adjacent parts. To be able to turn the opltical tube, it has on it a gearwheel 8, with W ich gears apinion on the upper end of a shaft 9, which is rotatable in a stuflingebox in'the bottom late of the chamber 0. These features, whicli serve to efl'ect the rotation of the optical tube independently of the hollow support 7 and the eyepiece, are notessential to the present invention and are illustrated in a copending application, said application and the present case'being divisions of my copending application, Serial N 0. 209,978, filed May 26, 1904.

The means for preventing condensation in the opticaljtube will now be described. The tight chamber 0 is connected by a pipe 10 With a holder 11 of dry air and by a pipe 12 with a pump 13. In the pipe 10 is a stoppipe 12 is a stop-valve '0'. To prevent moisture in the air, from condensing on and fogging the faces of the glasses or reflectors of the optical a paratus, the air may be first pumped from t the optical tube by the pump 13. The valve 12 is then closed and the valve v opened to ad mit artificially-dried air to the said chamber and tube. The air may flow freely between the optical tube and the chamber'O through one or more apertures 14 in the hollow support 7. These apertures serve-to connect the chamber O wit the hollow in'the support I 7 and this hollow or chamber is open to that in the optical tube. To assist in preserving the air in a dry state inthe chamber O, there may be set in it a receptacle 15 to contain a deliquescent salt. It may be stated here that the upper end of the optical tube is closed air-tight, so that when the 'air is removed from the instrument by the pump a nearly perfect vacuum will be formed therein into which the dried air rushes from th e holder.

This invention is notconcerned with any special means for drying the air, as it is not new to dry air and force it through the op tical tube of an altiscope providedwith a pressure-valve at its outer or upper end.

Having thus described my invention, I claim 1. A submarine boat, having an optical I instrument for receiving and deflecting an image down into the boat for observation at the eyepiece of the instrument, means connected with the instrument for exhausting the air from said instrument, and means for supplying to the latter artificially-dried air 1 3. The combination with an optical inafter the exhaustion has been made. strument, of a source of dry air and a suction- 2. A submarine boat, having an optical pump, each connected with said instrument, instrument for receiving and deflecting an and valves for res ectively controlling the 5 image down into the boat for observation at connections of sai pump and source with the eyepiece of the instrument, a pump 13 said instrument, whereby the dry air is supconnected with said instrument for exhaustplied to the instrument after the exhaustion ing the air therefrom, a holder 11 for dry air has been made. connected with said instrument for supplying In witness whereof I have hereunto signed 10 dry air in place of that removed by the pump, my name, this 24th day of December, 1904, and valves respectively controlling the pump in the presence of two subscribing witnesses. and holder connections with said instrument, LAWRENCE Y. SPEAK. whereby the dry air may be supplied to the Witnesses: instrument after the exhaustion has been BURGESS A. OR EDEN, 15 made. LEW O. MOORE. 

